Megan Fox abandoned her plan for a drug-free childbirth after she experienced her first "horrific" contraction when she went into labour in September (12).

The Transformers star was determined to be "really tough" by giving birth naturally, but she admits she began begging her husband Brian Austin Green for a numbing epidural when the unbearable pain kicked in.

She tells Access Hollywood, "It hurt so bad. It was so intense. And I thought I was gonna be really tough and make it, I was going to labour to eight centimeters... but the first contraction I got was horrific!

"I was screaming for an epidural when he (Green) was driving me to the hospital because my water broke on its own and immediately - it was level orange pain alert.

Megan Fox also reveals she took time to look her best before leaving home for the trip to the hospital, adding, "I was trying to blow dry my hair before I went to the hospital because I didn't want to go to the hospital with wet hair!"

The actress' first child, son Noah Shannon, was born on 27 September (12).